Optical printing device



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OPTXCL PRINTING DEVICE Filed Aug. 24,', l948 4 Sheets-Sheet 2 INVEN TGR.

March 2%? 1950 J. A. BALL OPTICAL mmm@ DEVICE 4 sheets-smet s Filed Aug.24, 1948 .IN V EN TOR.

. ,I Josephrthurall iwi/M? wif/HE ATTRNEY c3289 1950 J. A. BALL OPTICALPRNTNG DEVCE 4 Sheets-Sheet 4 Flsd Aug. $11 1948 ATTORNEY aan M... a, om

UNITED STATES PATENT OFFICE OPTICAL PRINTING DEVICE Joseph A. Ball, LosAngeles, Calif., assignor to E. I. du Pont de Nemours Company,Wilmington, Del., a corporation of Delaware Application August 24, 1948,Serial No. 45,885

1 Claim. (Cl. 88--20 This invention relates to photography and moreparticularly to an optical printing device. Still more particularly itrelates to an optical printing device for printing color separationrecords onto opposite light-sensitive strata of a photographic iilmelement.

An object of this invention is to provide a new and useful opticalprinting device. Another oblect is to produce such a device wherebycolor separation records can be successively printed in super-positioninto layers of a multilayer nlm element.' A further object is to producesuch a device wherein the recordsr can be printed in opposinglight-sensitive strata of a multilayer photographic element fromopposite directions.

The optical printing device of this invention is useful for printingcolor separation records in super-position or exact registration inseparate strata of a multilayer lm element. It permits one of therecords to be printed through the base of the film element and tworecords to be printed directly onto the emulsion surface or strata of ailm element. The printing device has a triangular path and is simple butaccurate in construction and operation. The device enables one to printrapidly and accurately three component color records, e. g., red, green,and blue, which are disposed in cycle sequence along a motion picturelm, onto a multilayer light-sensitive motion picture iilm in register.The novel optical printing device will now be described with referenceto the accompanying drawings which form a part of this specification andwherein the same reference numerals refer to the same parts throughoutthe several views.

In the drawings:

Fig. 1 is an elevation of the optical printing device and associatedmechanism mounted on a suitable frame;

Fig. 2 is a transverse section of a light-sensitive nlm which is exposedby the device of Fig. 1;

Fig. 3 is a plan view of the optical printing device and associatedmechanism for shifting the picture film;

Fig. 4 is an elevation of the sector wheel at the picture aperture withthe base and supporting frame in section;

Fig. 5 is an elevation of the nlm-shifting mechanism;

Fig. 6 is an elevation of the picture nlm-shifting mechanism with partsin section; and

Fig. 'l is an elevation of the vane-shifting mechanism of the triangularpath optical printing device; L

Fig. 8 is a. diagram of a vane sequence;

Fig. 9 is an elevation of a suitable shutter having a 170 opening.

Referring now more particularly to Figs. 1, 3, and 4, a frame I hasslidably mounted on machined ways 2 and 3 a base 4 for a picturefilmshifting mechanism. This base has a V-shaped groove 5 and a ilatportion E which interiit with the V-shaped and flat ways onV the frame.Additional ways l and 8 are provided on the frame for mounting thenlm-shifting mechanism, the triangular path printing device, or otherdevices. The base has secured to its bottom surface a heavy plate 9 bymeans of bolts ID. 'I'he plate has lateral flange portions l I which iitunder the rails i2 ci the frame and keep the base in firm operativecontact with the ways.

A base i3 ior the triangular path printing device is also similarlyslidably mounted on ways 2 and t of the frame. It may be retained by aheavy hanged plate similar to t if desired. The base is has an integralor separate bracket it which carries mirror i5. The base I3 also servesas a support for pivoted plate it which has a pair of prisms lil and I9mounted in raised portion il of its upper surface. Prism I8 has a30-609il triangular cross-section and prism I9 has the cross-section ofa truncated equilateral triangle. The two prisms are cemented togetherwith a partially reflecting partially transmitting metallic film inbetween. Together the prisms make a light splitting block capable ofsplitting entering rays into two parts and to reflect one part at anangle of with respect to the entering ray while permitting the otherpart to emerge without change of direction. 'I'he bracket is pivoted atits center near its outer end on pivot pin 20 which is mounted in abracket 20 which is afiixed to the base. The inner end of the bracketbase is reduced to form a tongue 22 which is disposed between two lugs23 and 24 which are integral with base I3. They, like bracket 20', maybe aixed to the base by means of bolts or screws or may be welded to thebase. Lug 23 has a cylindrical cavity 23 in which there is mounted aspring 25 which abuts against one side of the tongue. The other lug 24is screw-threaded and has set screw 26 threadably engaged therewith. Theinner end of the screw abuts on one side of the tongue. The screw issecured in adjusted position by means of locking nut 2l.

Base i3 also carries a third bracket 28 which has two holes 29 and 30which are disposed in the same horizontal plane near its upper edge.This bracket serves as a support for a mirror frame Il which is boltedto said bracket by means of spaced bolts 32 and 38 which pass throughholes 28 and 38 and are locked in position by means of nuts 84 and 85.The holes are larger than the bolts which permits some adjustment ofmirror frame 8| and also of mirror 88 which is carried thereby. Theinner end oi' frame 3| has a roller 81 in arcuate groove 88. The outerend oi.' the arm is pressed by a spring 38.

It will be noted that the centers of the cemented faces of prisms I8 andI8 form the apex of a 60 angle in the bifurcated optical axis, thebranches of which lead to mirrors i and 88, respectively. The surfacesof mirrors I5 and 38 are disposed so that light proceeding along theoptical axes is reflected from the surface of each at an angle of 60 tothe incident ray. The apexes at the mirrors together with thebifurcation at the prism form an equilateral triangle and a triangularpath for light which enters the system from a lamp along dotted axisA-A.

A pair of spaced bearings 48 and 4| are provided in the third bracket 28and in bracket 42 which is similarly welded. bolted. or screwed to baseI3. A reinforcing web 48 extends between ibrackets 42 and 28 as shown inFiaflof the drawing. This may be part of an integral casting with 42 orwelded. bolted. or screwed to brackets 28 and 42. Shaft 44 is journaledin the bearings and is turned bv means of gear 45 which is attached tothe shaft, e. g., by means of a set screw or key. The left end of theshaft carries two vane-actuating cams 48 and 41 which are spaced on eachside oi bracket 42 bv means of collar 48. The cams are attached to theshaft by means of a set screw or key so that they will rotate with theshaft and gear.

The upper end of bracket 42 is disposed at an anale and carries spacedpivot nins 48 and 58 which extend past each side surface. Cam followerlinlrs 5| and 52 are mounted on the lower pivot nin 48 by means of pivotholes 53 and 58 near their centers. The lower end of links 5| and 52carry rollers 54 and 55 which are iournaled on pins 58 and 51 near theend of follower links. Light-obstructing vanes 58 and 58 are Journaledon pivot pin 58 at the .upper part of bracket 42. These vanes are in theform of a bell crank and the short arms 88 and 8| carry pivot pins 82and 83 on which are mounted links 84 and 88 that are connected to theupper ends of cam follower links 5| and 52. respectively. by means ofpivot pins 88 and 81. The cam follower links and rollers are maintainedin operative association with the cam surface by means of tensionsprings 18 and 18 which are attached to hooks 88 and 88. on bracket 42and hooks 8| and 8|. and on cam follower links 52 and 5|. Vane 58 is cutaway as shown at 88 to allow passage of light when vane 58 is in itsupper position.

Cams 48 and 41 have their surfaces so designed that ythe vanes will moveup and down in a predetermined order. Their movement is correlated withthe film-shifting mechanism for the picturebearing film. The movement ofthe cams is correlated with a Geneva movement which shifts thelight-sensitive motion picture film, which is to be printed on, in acertain sequence.

The Geneva movement consists of a Geneva cam 82 with a cut-away portion83 which is adapted to receive the three points 84 of the Geneva starwheel 85. Slots 88 in the points are actuated by pin 81 on arm 88 whichis attached to and moves with the cam 82. The Geneva cam 82 and arm 88are mounted on shaft 44 and move 4 with the shaft and vane-actuatingcams 48 and 41 upon the turning of bevel gear 45. The latter gear mesheswith bevel gear 88 which is keyed to vertical operating shaft 88. Acollar 8| separates the hub of the bevel gear from base i8. Universallioints 82 and 88 connect shaft 84 to shaft 88 and a shaft which has abevel gear 88 at its lower end, which meshes in gear box 81 with bevelgear 88 on the end of horizontal shaft 88 having aV bevel gear |88 onits other end which meshes in gear box |8| with bevel gear |82 onvertical shaft |83 and is connected through universal joint |84 to shaft|85, which in turn is connected through universal joint |88 to verticalshaft |81 carrying bevel gear |88 which operates the picture-bearingfilm shifting mechanism. Gears 88 and 88 have a 3 to 1 ratio. Theoperation of such mechanism will be described later.

The Geneva star wheel in the triangular path printer is affixed to asprocket |88 which has two spaced sets of teeth |I8 and I|8' whichengage with the perforations in light-sensitive motion picture nlm Theshaft ends ||2 of the sprocket and star wheel rotate in bearings ||3 atthe upper ends of brackets ||4 and II4' which are fixed to base i3 bymeans of screws |I5. Spaced from brackets ||4 and ||4 are similarbrackets ||8 and ||8 which have bearings I|1 and ||1 near their upperends which receive the ends ||8 of guiding roller ||8 which has itsperiphery tangential to the plane of the film .,I as it passes betweenguide plates |28 and 2|. This plane also coincides with the plane of theprisms at their interface as more clearly shown in Fig. 3. Thelight-sensitive nlm moves in a definite predetermined manner which iscorre lated with the movement of the picture-bearing film which is to beprinted onto such light-sensitive nlm I I. This correlation isaccomplished by means of shafts 84 and |85 and the appropriatemechanism.

Shaft 88 is driven by means of gear |22 which meshes with gear |28 whichis driven through a multi-sneed clutch mechanism |24. the speed of whichis changeable by means of handle I 25. The clutch mechanism is driven bymeans of shaft |28 which contains a universal joint |21. The shaftpasses into gear box |28 which is driven by means of shaft |28 of motor|38 mounted on base |3I.

The mechanism for shifting the picture-bearing film will now bedescribed. This mechanism is mounted on a plate which has carefullymachined ways which are identical with those of plate I8. and theconstruction of such plate for convenience will not be repeated. Avertical housing |88 is integral with the plate and contains variousgears and cams for driving a shutter. filter wheel and the film-shiftingmechanism. The housing is not shown in Fig. 3 for the sake of clarity.However, in Fig. 4 the housing is shown with certain of the enclosedparts being present in outline. The housing has in one wall of anextension a rectangular opening |84 through which light rays'pass from asource of light. A plate |85 which carries registration pins |38 ismounted on the wall adjacent the opening |34 and has a similar opening|34'. A pair of film-guiding plates |31 and |38 which are carried by ayoke member |38 are also disposed adjacent the aperture. The lattermember has a tongue |48 which nts into lthe groove |4| of cam |42 Thiscam is mounted on a shaft |48 which also carries heart-shaped cam |44. Ayoke |45 nts around the latter cam and has a U-shaped plate |46 whichcarries pins |41 which.

pass through the perforations in the picturebearing film |48. Uponrotation of the shaft, the cam |42 causes the film and guide plates tomove to the left and seat upon registration pins |36. While so seated,light rays pass through the lm and to the triangular path printingdevice. While the printing operation is proceeding,

`a further turning of cam |44 then moves yoke |45 and plate |46downwardly until pin |41 has moved a full picture frame andlis oppositethe corresponding perforation of the next picture frame in the motionpicture lm. Cam |42 then moves the guide plates and film to the rightoff pins |36 and onto pins |41. Upon further rotation of the shaft, cam|44 moves yoke |45, plate |46 and the film upwardly the distance of oneframe and the movement just described repeats itself. The film-shiftingdevice just described is an old and well-known mechanism and isdescribed in Howell U. S. Patent 1,038,586.

Shaft |43 is mounted in suitable bearings |49 and |49 and has attachedto it a gear |5|. Rotatably mounted on shaft |43 but not attachedthereto is a drum |32 carrying a filter wheel |52 and gear |50. Thisdrum is held in place by means of a nut |53. Mounted also on shaft |43and fastened to it is a shutter |52 which serves to cut oif theillumination during film shifting, The filter wheel |52 has threesegmental openings |54, |55, and |56 adapted to receive colored gelatinor glass filters to color the printing light in any desired manner. Theshutter |52' and camshaft |43 turn once for each picture frame. Thefilter Wheel |52, however, turns at 1/3 of the speed of the shutter andcamshaft so that 'the three openings in the filter wheel are broughtsuccessively into the light beam.

Gears |50 and |5| mesh with gears |51 and |58, respectively, which aremounted on parallel shaft |59 which is journaled in bearings |60 and|60'. The latter gears mesh with gear |6| on parallel shaft |62 which issimilarly journaled in bearings |63 and |64. rPhe left end of the shaftcarries bevel gear |65 which meshes with bevel gear |08 which is drivenby motor |30 through the gear and drive shaft arrangement shown.

A bracket |61 is fastened to base I3. It supports tube |61' which inturn carries a lens mount |68. Lens |69 is fixed in the mount and itsoptical axis passes through the approximate center of aperture |34 andhence through the center of each successive picture frame. Light from anincandescent lamp which is mounted on a base |1| on bracket |12 on frameis directed along the optical axis A-A by reflector |13.

A lrn element as shown in Fig. 2 of the drawing is threaded through theguide plates |20 and |2| and over sprocket |09 and roller ||9 of thetriangular path printer. This film has three emulsion layers, |14, |15,and |16, which may be, for example, sensitive to biue, red, and bluelight, respectively. Blue-sensitive emulsion layer |14 faces mirror |5.Film element |48 which bears red, green, and blue color component silverimage records in cycle sequence is placed on registration pins |36opposite projection aperture |34. Light passes from lamp |10 through redfilter segment |54 of the filter wheel and encounters the blue record onfilm |48 which is therefore printed in layer of film while vane 59 is upand vane 58 is dwn. Shaft |43 is turned and the green record is shiftedbefore aperture |34 and printed by light passing through the clearopening |55 onto layer |16 lil) .114. As the blue picture record in thenext sequence in lm |48 is shifted before the aperture, film is shiftedone frame by means of the co-action of cam arm and star wheel. Theaction of the vane cams and star wheel cam are shown schematically inFig. 8 of the drawing. This figure is self-explanatory.

Shafts 94 and |05 are driven by means 0f shaft 99 through gears |00 and|02 and gears 98 and 96. The latter gears have a 3 to l ratio therebymaking shaft |05 revolve at three times the speed of shaftl 94. By thisarrangement the positivo or picture-bearing film moves one frame forevery three frames that the negative film moves. One complete revolutionof the cam shaft (which corresponds to three revolutions of the shuttershaft at the negative aperture) will give a complete cycle operation ofthe vanes and advance the positive film one frame during each suchrevolution.

' In Fig. 7 the device is ready to print the green record onto thelight-sensitive film. This position is shown in order to better portraythe position of the vanes in an operative printing position.

While a Geneva cam and star wheel has been shown for actuating thefilm-shifting sprocket, the invention is not limited to such a mechanismas other gear, cam and/or linkage mechanisms can be used in placethereof. Similarly, vane shifting gears, cams, and/or linkages can besubstituted for that shown.

The triangular path printing device is, of course, mounted in a suitablelight-proof housing so that the light rays will not expose the positivefilm except during the brief intermittent periods when it passes thepositive aperture when printing is effected.

A unique feature of the apparatus is that there is no motion of theduplitized or duplicoated positive lm while the printing of all threecomponents is carried out. It is not necessary, therefore, to haveregistration pins at the positive printing aperture. Furthermore,printing at the negative aperture requires only one pair of pins onwhich the three component pins are brought to position successively.Thus, the registration problems are considerably simplified as comparedwith a contact registering printer.

The apparatus is simple and e'ective and once set requires no attention.It is entirely automatic and reliableY and enables one to continuouslyprint three color separation records in cycle sequence in register.

Instead of having two film sprockets as shown in Fig. 7, roller ||9 canbe eliminated and the star wheel and sprocket disposed in line with lmif desired. This can be accomplished by shifting the shaft 44 andattendant mechanism by varying the size of the cam and star wheel, etc.

What is claimed is:A

An optical printing apparatus comprising the combination of a motionpicture film-shifting mechanism, shutter and 3-unit filter sector wheelfor regularly shifting a picture-bearing motion picture lm in a regular3-cycle frame sequence with a triangular path printer comprising acopying lens, a light-dividing prism and two mirrors which are disposedso that the reflected and transmitted branches of the optical axis ofthe lens through the prism form an equilateral triangle, a illm guideand aperture in the focal plane between the two mirrors, thelight-dividing surface of the prism being coplanar with the aperturewherein the illm to be printed is situated, and the intersection of thisplane with the normals to the two mirrors forming angles of 120 each,said intersection forming the center of an equilateral triangle whoseapices are the center of the mirrors and the center of the lightdividingsurface, means for shifting the illm frame by frame at the apertureactuated by a Geneva star wheel, a cam follower and arm for actuatingthe Geneva star wheel, a lightobstructing vane in the optical path fromthe prism to the first mirror and a light-obstructing vane in theoptical path from the said prism fc the second mirror, cam means foractuating said vanes in a regular cycle sequence which is correlatedwith the film-shifting mechanism for the picture-bearing film, saidshutter turning once for each picture frame and said iilter wheelturning at one-third the speed of the shutter and of the Geneva cam andvane shifting cams.

JOSEPH A. BALL.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Brewster Apr. 13, 1926

